Questions tagged [cisco-nexus]

For questions about the Cisco network product line, called Nexus. For instance, Cisco Nexus 3000, 4000, 5000, 6000, 7000 and 9000.

Filter by
Sorted by
Tagged with
6 votes
1 answer
1k views

NX-OS 9.3: ECMP polarization and "ip load-sharing ... rotate"

This is a "why and how exactly does this work" question. The given problem is already solved. QUESTION: I'm interested to understand what "rotate" in ip load-sharing address source-...
user avatar
6 votes
1 answer
963 views

Cisco NX-OS 9K - LDAP Configuration

I'm having some trouble configuring LDAP authentication (via Windows AD) when connecting via ssh on our CISCO. I replaced some information from the switch, you will see it in uppercase here. ...
user avatar
5 votes
1 answer
1k views

How to resolve a spanning tree issue on a server trunk port?

I am having a very strange spanning-tree issue with Cisco Nexus switches. My server is connected to the TOR switch with trunk configuration because we have multiple VLANs on the server. When I reboot ...
user avatar
  • 4,227
5 votes
0 answers
412 views

Cisco nexus 9396 rebooted with reason xbar_client

Today my one of cisco nexus 9396PX switch got rebooted and this is what i found, based on following logs what could be wrong? We don't have Cisco support for this switch, trying to see if i can get ...
user avatar
  • 4,227
4 votes
2 answers
2k views

Nexus 3172T MTU

I am attempting to set the L3 mtu on a Nexus port. The mtu option is only available if I set "no switchport" which then prevents me configuring VLAN related settings. Am I missing something obvious? ...
user avatar
  • 127
4 votes
1 answer
273 views

How can I upgrade Cisco Nexus switch if not enough space for new image?

I have Nexus 92348GC-X units with 9.3.7 image version and I need to upgrade them, BUT not enoght space on this devices for new image upload (nxos 9.3.9) Moreover, I can't delete old image after I ...
user avatar
4 votes
1 answer
2k views

Cisco Nexus 9300 TCAM carving

I have Cisco Nexus C9396PX L3 switch and i have configured bunch of ACL (inbound) on it to deny/permit traffic. now if i am trying to add more ACL then getting error that your TCAM table is full. here ...
user avatar
  • 4,227
4 votes
1 answer
439 views

Strange flooding during installing new switch in network

This is very strange issue i am noticing. In our datacenter we have every switch in rack has cisco vPC configured in short whole datacenter running vPC so there is no loop for spanning-tree anywhere ...
user avatar
  • 4,227
4 votes
1 answer
127 views

Cisco NX-OS licensing

I'm somewhat new to networking and I have been looking to pick up an older Nexus switch to learn more about it and the converged features. I found a Nexus 3048 (for what I assume to be a reasonable ...
user avatar
  • 41
4 votes
1 answer
2k views

How to announce network to specific neighbor peer in BGP

I have following scenario where i already have 10G (A - BLUE Link) connectivity from ISP on SW1 and SW2 for redendency and i have configured eBGP and iBGP, Everything is good at this point, Now my ...
user avatar
  • 4,227
4 votes
1 answer
2k views

Finding the root cause of Spanning-Tree recalculations (on Cisco Nexus 9000s)

I have a nagging Rapid PVST problem on some Nexus 9000 switches. Rapid-PVST keeps recalculating 3 to 5 times an hour. We have in this topology (summarized): Edge Router ...
user avatar
4 votes
1 answer
787 views

Cisco switch ports configuration with QSFP+ to (4) SFP+ Hydra Cable Assembly

I am connecting two cisco switches with QSFP+ to (4) SFP+ Hydra Cable Assembly. On one side I have Nexus N3K series switch with QSFP+ port and on other side I have 6500 series switch with SFP+ ports. ...
user avatar
  • 812
4 votes
2 answers
570 views

NTP architecture questions

I have a question about NTP. We want to setup our core switches as NTP master for our network. We have three data centers. Site A : Two Nexus as core Site B : two Nexus as core Site C : two 6800 (in ...
user avatar
  • 43
4 votes
2 answers
11k views

Cisco Nexus vPC LACP bonding with server issue

I am configuring vPC end to end till my server to get more bandwidth, and following is my scenario I am seeing one strange thing which is i configured vPC on N3k switch and then i configured my Linux ...
user avatar
  • 4,227
4 votes
1 answer
4k views

Cisco Nexus 7k as NTP server

Anyone have experience with setting up their Nexus 7k core as an NTP server? I was thinking the code would look like below: ntp master stratum 2 ntp server ns.arc.nasa.gov prefer ntp server bitsy....
user avatar
3 votes
2 answers
319 views

Looking for a sanitized Cisco NXOS configuration

This may sound a bit unusual, but I'm looking for someone who can answer with a sanitized NXOS configuration with the following features used: vPC FEX EIGRP, OSPF or ISIS (IPv4) HSRP or VRRP This ...
user avatar
3 votes
2 answers
595 views

Control plane terminology - Cisco Nexus

Is it true to speak about layer 2 control plane (LACP, STP, etc), and layer 3 control plane (OSPF, EIGRP, etc) ? or do we have only a general control plane ? We know Cisco Nexus vPC cluster has a ...
user avatar
  • 1,075
3 votes
2 answers
393 views

UDLD on Nexus 5548 and Nexus 2232

Do you know if I turn on UDLD the 5K and 2K will speak UDLD to each other and do you feel this is a benefit to detect any link issues between the 5K and the FEX? Thanks
user avatar
  • 311
3 votes
1 answer
614 views

BGP running on VLAN interface or loopback0?

The switches mention below are all Cisco. I got sw01 and sw02 running BGP peering with multiple service provider for our internal infrastructure, between sw01 and sw02 have a port-channel group 100. ...
user avatar
3 votes
1 answer
2k views

Cisco nexus 3048 SFP validation failed

I have cisco Nexus 3048TP switch (48x1G + 4x10G) Hardware cisco Nexus 3048 Chassis ("48x1GE + 4x10G Supervisor") Intel(R) Celeron(R) CPU P4505 @ 1.87GHz with 3665240 kB of memory. ...
user avatar
  • 4,227
3 votes
2 answers
948 views

vPC traffic flow question

This is going to be new network in my datacenter and i have question related vPC, as you can see i have A1/A2 switch (L3/L2 routing) in aggregation layer and C1/C2 switches for Core (L3 routing). I am ...
user avatar
  • 4,227
3 votes
2 answers
268 views

Applying a queuing service policy

This is on a Nexus N5624Q. I have this TA-queuing service policy : policy-map type queuing TA-queuing class type queuing queue-cos1 bandwidth percent 20 class type queuing queue-cos2 ...
user avatar
  • 767
3 votes
1 answer
9k views

interface showing "Link not connected" on a Nexus 2200 FEX but it is very much connected

I have to be over looking something dumb here but I can't figure it out. The fex is set up properly and is communicating to the Nexus 5548 without issue. There are a few other fexs connected as well. ...
user avatar
  • 754
3 votes
1 answer
366 views

TCAM carving question for Cisco Nexus 9396PX

TCAM carving question for Cisco Nexus 9396PX I have Cisco Nexus 9396PX and configure for IPv4 with IPv4 RACL on SVI to block some basic traffic. Now i have configured IPv6 and trying to configure ...
user avatar
  • 4,227
3 votes
2 answers
2k views

What is Interface's Nominal Bitrate?

If you check show int tranceiver command on Nexus Switch 10Gbit Ethernet port, the output shows the nominal bitrate is 12000 MBits/sec instead of 10000 MBits/sec. As I know 12 bytes Interframe Gap + 8 ...
user avatar
3 votes
1 answer
76 views

Cisco N3K-C3064 RACL question

I have a cisco nexus n3k-c3064pq-10gx and i want to have an acl and add 270x line (they will drop my interface vlan IP address because they are public IP), I want to know can I have this acl with 270x ...
user avatar
3 votes
1 answer
942 views

VXLAN on top of EIGRP/I-BGP

for labbing purposes, I have two NX-9000 that's connected to each other via EIGRP. Trying to have one as Spine switch and the other as Leaf switch. No redundancy/HA needed at the moment Could you ...
user avatar
3 votes
1 answer
252 views

Tapping Nexus 5k FEX uplinks

Very similar to this question, we are considering tapping the FEX uplinks that we have running from Top Of Rack to our Nexus 5k core switches. Has anyone had success with tapping those uplinks? I ...
user avatar
3 votes
1 answer
489 views

vPC over Dark Fiber

Recently, I was asked to implement vPC connections over Dark Fiber between two data centers. Is this possible, and, if it is possible, does it have any drawbacks or limitations? I'm asked to encrypt ...
user avatar
  • 3,404
3 votes
2 answers
121 views

Stop Memcrashed amplification DDoS attack

DDoS is essential part of my life so i am back with more question, Yes we started getting memcache based UDP amplification attacks, all source ports are 11211 coming from many random source IPs, we ...
user avatar
  • 4,227
3 votes
1 answer
451 views

Mirror traffic from few interfaces in nexus 3000 switch to 2 interfaces for IPS

I need to be able to mirror traffic from 4 ports on Cisco Nexus 3000 switch to 2 ports on a same switch and connect 2 IPS appliances to those 2 ports. But I don't think it is possible to mirror port ...
user avatar
  • 175
3 votes
1 answer
2k views

How to copy an image to a corrupt bootflash?

Hi i am trying to copy an image from my ftp server onto a nexus 3500 switch (N3K-C3048TP-1GE) but the switch will not let me access the bootflash at all, is there anything I can do to recover the ...
user avatar
3 votes
5 answers
180 views

Cisco N9K - Down an interface in response to another interface going down?

I currently have my transit providers plugged directly into my router. I really like this arrangement because when the ISP goes down this typically downs the interfaces which results in BGP peering ...
user avatar
3 votes
0 answers
468 views

TCAM utilization on Nexus 9396 switches

I have Cisco Nexus 9396 switch which is running L3 mode and i have configured bunch of IPv4 access-list in Ingress for firewalling to block certain traffic. I am reading about TCAM and wanted to ...
user avatar
  • 4,227
2 votes
1 answer
153 views

ACL on Nexus 3064PQ performance

We are using this switch as L3 and planning to run some ACL to stop bad traffic. I never run ACL on switches so wondering is there any performance impact or how bad it will be? if anyone has any ...
user avatar
  • 4,227
2 votes
2 answers
1k views

Nexus 7000 - switchport Voice configuration

Nexus 7k NXOS 6.2(8a) I am trying to configure a voice vlan but the command does not seem available? Is there something I am missing to enable that? interface Ethernet4/1 description ...
user avatar
  • 313
2 votes
1 answer
829 views

Cisco Nexus C9396PX licence question

We have Cisco Nexus C9396PX and i want to run HSRP on this to do failover, I just looked at licence and its showing following does that mean switch has activated Layer 3 license? switch# show lic u ...
user avatar
  • 4,227
2 votes
1 answer
89 views

Fabric Extender for Peer-Link on vPC domain (two Nexus 5000 switches)

I have two Nexus 5000 series switches. My question lies with the Peer Link. My intentions are to use e1/31 and e1/32 on both switches as the peer link. Here are the exact SFPs that I am using for ...
user avatar
  • 123
2 votes
1 answer
5k views

Cisco N9K Output Discards

We're experiencing output discards in couple of our N9K-C9372PXs. Seems like egress queues fills and it ends up in a lots of discarded packets. All interfaces where discards occur are NEXUS ...
user avatar
  • 103
2 votes
2 answers
421 views

BGP multi-path using loopback

I have above scenario where i have multiple PATH for my BGP so i have to setup loopback interface to make it ECMP routing on both path. I have cisco nexus switches and following is my first router ...
user avatar
  • 4,227
2 votes
1 answer
2k views

Cisco nexus vpc spanning-tree port type trunk question

I have very strange scenario here which you can see in diagram. SW1/2 is Cisco nexus 3064PQ switch configured in vPC and those switch connected to SW3/4 ( HP 6120XG ) switches on HP c7000 blade ...
user avatar
  • 4,227
2 votes
1 answer
5k views

default interface cmd on cisco nexus 5k

Does anyone know of an equivalent "default interface X" comand for the Cisco Nexus 5000 platform? switch>en switch# conf t switch#(config)# default interface x -> dead thread here about the ...
user avatar
  • 827
2 votes
2 answers
2k views

Nexus 5500 FEX Support

This design guide on networkcomputing.com states the following: When uplinking to Nexus 5Ks, one topology option is to dual-home the physical Fabric Extender. Dual-homing a FEX provides path ...
user avatar
  • 1,005
2 votes
1 answer
806 views

Is it possible to make a truly active\active L3 VRRP\HSRP configuration between two Nexus in a vPC

I'm an admin that is used to working with older Cisco gear, the Catalyst 6500 and the like. This is my first time diving into the world of nxOS. I'm trying to create a truly active\active ...
user avatar
2 votes
2 answers
856 views

NXOS DHCP Relay - overwriting Option 54 (Server Identifier) differently in DHCPDISCOVER vs. DHCPREQUEST?

I'm trying to sort a DHCP relay problem in a VLXAN/EVPN environment (Cisco N9K, NXOS 9.3.2). We seem to be able to get DHCPDISCOVERs through to the server and DHCPOFFERS back from there. DHCPREQUESTs ...
user avatar
2 votes
1 answer
738 views

Cisco nexus 9396PX TX output discard on 40G interface without link congestion

We have cisco nexus 9396PX with N9K-M12PQ module (12x40G Interface), We have 8x10G L3 LACP bonded connectivity with our ISP and so far so good no issue at all. but recently we migrated that LACP LAg ...
user avatar
  • 4,227
2 votes
1 answer
69 views

QSFP BiDi 40GB with two LC-LC

This Cisco module QSFP-40G-SR-BD is Bi-Directional (BiDi) 40Gbps QSFP, which means a single link used for RX & TX, each link 20Gbps, two LC links in total gives 40Gbps connection. If we will use ...
user avatar
  • 121
2 votes
1 answer
1k views

Multiple HSRP group on same VLAN interface

I have Cisco Nexus 9k switch and following is my HSRP configured with vPC interface Vlan100 description *** Public_1 VLAN *** no shutdown mtu 9216 no autostate no ip redirects ip address ...
user avatar
  • 4,227
2 votes
2 answers
3k views

Cisco ASA vPC configuration issue

I have this scenario and trying to configure vPC for Cisco ASA 5585 (Active-Standby) Nexus vPC config: interface port-channel1 switchport mode trunk switchport trunk allowed vlan 10 speed ...
user avatar
  • 4,227
2 votes
1 answer
169 views

Routing the same prefix to different destinations on the same router

I have a Cisco Nexus 7000 and have configured static routes to reach my internal networks on the Nexus 7000. During a DDOS attack, the Nexus 7000 receives a more specific route via IBGP to re-route ...
user avatar
  • 21